This invention generally relates to intravascular procedures, such as percutaneous transaluminal coronary angioplasty (PTCA), and particularly to the exchange of guidewires during such procedures.
In typical PTCA procedures, a dilatation catheter is advanced over a guidewire, which is slidably disposed within an inner lumen of the dilatation catheter, into the patient's coronary artery until the balloon on the distal extremity of the dilatation catheter is properly positioned across the lesion to be dilated. Once properly positioned across the lesion, the flexible, relatively inelastic balloon on the dilatation catheter is inflated to a predetermined size with radiopaque liquid at relatively high pressures (e.g., generally 4-20 atmospheres or more) to dilate the stenosed region of the diseased artery. One or more inflations of the balloon may be required to complete the dilatation of the stenosis. After the last dilatation, the balloon is deflated so that the dilatation catheter can be removed from the dilated stenosis and blood flow can resume through the dilated artery.
One significant improvement in dilatation catheters has been the introduction of rapid exchange type dilatation catheters. These catheters have a short guidewire receiving sleeve or inner lumen extending through the distal portion of the catheter which extend from a distal guidewire port in the distal end of the catheter to a proximal guidewire port spaced proximal to the proximal end of the dilatation balloon. The proximal guidewire port is usually located at least about 10 cm and usually not more than about 50 cm from the distal guidewire port. A slit is preferably provided in the catheter wall in fluid communication with the guidewire receiving inner lumen which extends from the second guidewire port, preferably to a location proximal to the proximal end of the inflatable balloon to aid in the removal of the catheter from a guidewire upon withdrawal of the catheter from the patient. The structure of the catheter allows for the rapid exchange of the catheter without the need for the use of an exchange wire or adding a guidewire extension to the proximal end of the guidewire. The design of this catheter has been widely praised by the medical profession and has met with much commercial success in the market place because of its unique design. The rapid exchange type dilatation catheters of the assignee of the present invention, Advanced Cardiovascular Systems, Inc., have had a significant impact in the market for rapid exchange type dilatation catheters. Such products include dilatation catheters sold under the trademarks ALPHA, STREAK and ELIPSE.
Rapid exchange type dilatation catheters are described and claimed in U.S. Pat. No. 5,040,548 (Yock), U.S. Pat. No. 5,061,273 (Yock), U.S. Pat. No. 5,300,085 (Yock), U.S. Pat. No. 5,350,395 (Yock), U.S. Pat. No. 4,748,982 (Horzewski et al.), U.S. Pat. No. 5,154,725 (Leopold) and U.S. Pat. No. 5,346,505 (Leopold) which are incorporated herein in their entirety by reference.
However, there is one significant inconvenience with the use of rapid exchange type dilatation catheter systems, namely, the inability to remove a guidewire already in place within a patient's vasculature during an angioplasty procedure without losing access to the vascular location. There has been no convenient way in which a replacement guidewire might be advanced through the vasculature and into the short guidewire receiving inner lumen in the distal extremity of a rapid exchange type dilatation catheter. These instances occur when there is a need to replace an in-place guidewire with another guidewire having a different structure, e.g. from a floppy-type design with a separate shaping ribbon to an intermediate or standard with a core wire which extends to the distal tip of the guidewire. The need to withdraw an in-place guidewire also occurs when the distal tip of the in-place guidewire needs to be reshaped to change the angle of attach to a branch coronary artery.
What has been needed and heretofore unavailable is a convenient means to withdraw an in-place guidewire from a rapid exchange type dilatation catheter and either replace the in-place guidewire with another guidewire or to reposition the in-place guidewire within the rapid exchange type dilatation catheter. The present invention satisfies these and other needs.